Film-forming apparatus and film-forming method

ABSTRACT

A film-forming apparatus and film-forming method comprising a film-forming chamber for being supplied a reaction gas, a substrate placed on a susceptor in the film-forming chamber, a heater for heating the substrate, a transfer chamber adjacent to the film-forming chamber, transferring the substrate to the film-forming chamber, measuring the temperature of the substrate, rotating the substrate via the susceptor, a detecting unit for detecting rotating direction and angle of the rotating unit, generating data of the substrate using temperature data of the substrate measured by the temperature-measuring unit while the substrate is rotating, and positional data of coordinates at which temperature is measured, generated based on the rotating direction and angle, acquiring data of the movement direction and amount of positional error of the substrate based on the data, a control unit for adjusting position of the transfer unit based on the amount of position error of the substrate.

CROSS-REFERENCE TO THE RELATED APPLICATION

The entire disclosure of the Japanese Patent Application No. 2011-217895, filed on Sep. 30, 2011 including specification, claims, diagrams, and summary, on which the Convention priority of the present application is based, are incorporated herein in its entirety.

FIELD OF THE INVENTION

The present invention relates to a film-forming apparatus and a film-forming method.

BACKGROUND

Epitaxial growth technique is conventionally used to produce a semiconductor unit such as a power unit (e.g., IGBT (Insulated Gate Bipolar Transistor)) requiring a relatively thick crystalline film.

In the case of a vapor-phase growth reaction used in epitaxial growth technique, a wafer is placed inside a film-forming chamber maintained at atmospheric pressure or a reduced pressure, and a reaction gas is supplied into the film-forming chamber while the wafer is heated. As a result, a pyrolytic reaction or a hydrogen reduction reaction of the reaction gas occurs on the surface of the wafer so that an epitaxial film is formed on the wafer. The gas generated by the reaction, as well as the gas not used, is exhausted through the outer portion in the chamber. After the epitaxial film is formed on the wafer, the wafer is carried out from the chamber. Another wafer is then carried into the chamber, and then an epitaxial film will be formed on that wafer.

In order to produce a thick epitaxial film in high yield, a fresh reaction gas needs to be continuously brought into contact with the surface of a uniformly heated wafer to increase a film-forming rate. Therefore, in the case of a conventional film-forming apparatus, a film is epitaxially grown on a wafer while the wafer is rotated at a high speed (see, for example, Japanese Patent Application Laid-Open No. 2008-108983).

FIG. 10 is a schematic cross-sectional view of a conventional film-forming apparatus. It refers to a state in which the substrate is carried out (or into) the chamber.

As shown in FIG. 10, a film-forming chamber 201 has a belljar-shaped body 302 positioned on a base plate 301 in the film-forming apparatus 200. A base plate cover 303 is positioned and is detachable from the base plate 301, the base plate cover 303 has a shape and size which can cover the whole of the base plate 301. The base plate cover 303 may consist of, for example, quartz. The base plate 301 is connected to the belljar-shaped body 302 via a flange 210. The flange 210 is sealed with packing 211. During the vapor-phase growth reaction, the temperature will be very high in the film-forming chamber 201. Therefore, flow channels 203 for circulating cooling water for cooling the film-forming chamber 201 are provided in the base plate 301 and the belljar-shaped body 302.

A supply portion 205 for supplying a reaction gas 204 is positioned in the belljar-shaped body 302. The discharge portion 206 is positioned in the base plate 301. The resulting reaction gas, after the reaction, and the reaction gas not used in the reaction are exhausted out of the film-forming chamber 201 through the discharge portion 206.

The discharge portion 206 is connected to a pipe 212 via the flange 213. The flange 213 is sealed with packing 214.

A liner 202 is positioned in the film-forming chamber 201. The liner 202 is positioned between an inner wall of the film-forming chamber 201 and a space ‘B’ in which the epitaxial reaction is performed on the substrate 207. A rotating shaft 216, and a rotating cylinder 217 positioned on the top of the rotating shaft 216, are positioned in the liner 202. A ring-shaped susceptor 208 is attached to the rotating cylinder 217. The rotating shaft 216 rotates, and then the susceptor 208 will be rotated via the rotating cylinder 217.

The susceptor 208 has a counterbore provided thereon so that the outer periphery of the substrate 207 can be positioned in the counterbore. During the vapor-phase growth reaction, a substrate 207 is placed on the susceptor 208, and then the substrate 207 will be rotated with the rotation of the susceptor 208.

The liner 202 includes an upper opening into which a shower plate 215 is fitted to act as a flow-straightening vane to uniformly supply the reaction gas 204 to the surface of the substrate 207. The reaction gas 204 flows through the shower plate 215 flows downward toward the surface of the substrate 207. As a result, a pyrolytic reaction or a hydrogen reduction reaction occurs on the surface of the substrate 207 so that an epitaxial film is formed on the surface of the substrate 207.

A heater 209 positioned in the rotating cylinder 217 heats the substrate 207; the heater 209 is supported by an electrically conductive arm-like busbar 220. The heater base 221 at the opposite side of the heater 209 supports the busbar 220. The conductive connecting portion 222 connects the busbar 220 and a rod electrode 223. Electricity is conducted from rod electrodes 223 through the busbar 220 to the heater 209. The temperature of the substrate 207 is measured by a radiation thermometer 224 a and 224 b.

After the epitaxial film is formed on the substrate 207, the reaction gas 204 in the film-forming chamber 201 is replaced with hydrogen gas or inert gas. The substrate 207 is then carried out of the film-forming chamber 201.

The liner 202 has a substrate transfer portion 246, and the belljar-shaped body 302 has a substrate transfer portion 247. A transfer chamber (not shown) is adjacent to the film-forming chamber 201. When the substrate 207 is carried out of the film-forming chamber 201, the substrate 207 is moved upwards by a substrate-supporting portion (not shown) in the rotating cylinder 217. A transfer arm 248 of a transfer robot is then inserted into the film-forming chamber 201 via the substrate transfer portions 246 and 247. The substrate 207 is then transferred from the substrate-supporting portion to the transfer arm 248 and carried out of the film-forming chamber 201 through the substrate transfer portions 246 and 247.

After the substrate 207 is transferred, the next substrate 207 on which an epitaxial film will be formed is carried in the film-forming chamber 201. Specifically, the transfer arm 248 supporting the substrate 207 is inserted into the film-forming chamber 201 through the substrate transfer portion 246, 247. Next, the substrate 207 is transferred from the transfer arm 248 to the substrate-supporting portion. The position of the substrate-supporting portion is lowered, as a result placing the substrate 207 on the susceptor 208. At that time, the position of the transfer arm 248 is adjusted so that the center of the substrate 207 will be aligned with the center of the susceptor 208.

When the substrate 207 is transferred into the film-forming chamber 201, the temperature of the transfer chamber is about at room temperature, however the temperature of the film-forming chamber 201 is higher than the transfer chamber, for example, about 800° C. Therefore, the substrate 207 transforms as a result of the rapid change of temperature after the substrate 207 is transferred from the transfer chamber into the film-forming chamber 201. As a result of this temperature change the substrate 207 moves on the transfer arm 248 or on the substrate-supporting portion, and the substrate 207 is subsequently out of the position that was adjusted in the transfer chamber. The substrate 207 is placed on the susceptor 208 while positioned incorrectly, and the center of the substrate 207 does not align with the center of the susceptor 208. Therefore the distance from the substrate 207 to the sidewall of the counterbore of the susceptor 208 will not be uniform along the circumference of the susceptor 208.

The following problem occurs when the epitaxial reaction is performed when that the center of the substrate 207 isn't aligned with the center of the susceptor 208.

The reaction gas 204 introduced into the film-forming chamber 201 flows radially across the top surface of the substrate 207 from the center portion to the peripheral portion of the top surface due to the centrifugal force generated by the rotation of the substrate 207, and exits from the film-forming chamber 201 through the discharge portion 206. At that time, part of the gas that reaches the peripheral portion of the substrate 207 gathers where the substrate 207 is close to the sidewall of the counterbore of the susceptor 208, resulting in the formation of an epitaxial film between the substrate 207 and the susceptor 208. This film acts to attach the substrate 207 to the susceptor 208, which may cause a crystal defect called a “slip” in the substrate 207, as well as hampering the transfer of the substrate 207. The “slip’ can warp the substrate 207 and generate a leakage in an IC unit, thereby greatly reducing the yield of an IC unit.

The present invention has been made to address the above issues. That is, an object of the present invention is to provide a film-forming apparatus and a film-forming method that can place the substrate on a predetermined position on the susceptor.

Other challenges and advantages of the present invention are apparent from the following description.

SUMMARY OF THE INVENTION

The present invention relates to a film-forming apparatus and a film-forming method.

The first embodiment comprising a film-forming apparatus, a film-forming chamber for being supplied a reaction gas, a susceptor for placing a substrate on, provided in the film-forming chamber, a heater for heating the substrate, provided below the susceptor, a transfer chamber being adjacent to the film-forming chamber, a transfer unit for transferring the substrate to the film-forming chamber, provided in the transfer chamber, a temperature-measuring unit for measuring temperature of the substrate, a rotating unit for rotating the substrate via the susceptor, a detecting unit for detecting rotating direction and rotation angle of the rotating unit, a analysis unit for generating data of the substrate using temperature data of the substrate measured by the temperature-measuring unit while the substrate is rotating, and positional data of coordinates at which temperature is measured, generated based on the rotating direction and the rotation angle detected by the detecting unit, and acquiring data of the movement direction and an amount of positional error of the substrate based on the data, a control unit for adjusting position of the transfer unit based on data of the movement direction and the amount of position error of the substrate.

Further to a first embodiment of this invention, the film-forming apparatus wherein the analysis unit determines whether the amount of positional error is at an allowable value or less than the allowable value, and sends data of the movement direction and the amount of positional error to the control unit if the amount of positional error is more than the allowable value.

Further to a first embodiment of this invention, the film-forming apparatus wherein the temperature-measuring unit has a radiation thermometer provided outside the film-forming chamber to measure a temperature of the substrate, by receiving radiant light from the substrate.

Further to a first embodiment of this invention, the film-forming apparatus wherein the location of temperature measurement on the substrate, performed via the second radiation thermometer, is capable of being moved.

Further to a first embodiment of this invention, the film-forming apparatus wherein the location of temperature measurement on the substrate by the second radiation thermometer is capable of moving a predetermined distance.

Further to a first embodiment of this invention, the film-forming apparatus wherein the temperature-measuring unit has a first radiation thermometer for measuring a temperature of the center position of the substrate by receiving the radiant light from the substrate, and a second radiation thermometer for measuring a temperature of the periphery of the substrate.

Further to a first embodiment of this invention, the film-forming apparatus wherein the location of temperature measurement on the substrate, performed via the radiation thermometer, is capable of being moved.

Further to a first embodiment of this invention, the film-forming apparatus wherein the location of temperature measurement on the substrate is capable of moving a predetermined distance.

Further to a first embodiment of this invention, the film-forming apparatus wherein the heating unit has a first heater for heating the substrate, and a second heater for heating the periphery of the substrate.

A second embodiment of this invention, a film-forming method comprising: transferring a substrate into a film-forming chamber via a transfer unit, and placing the substrate on a susceptor by a substrate-supporting portion, measuring a temperature of the periphery of the substrate while the substrate is rotating and detecting the rotating direction and rotation angle of the substrate, generating temperature data of the substrate based on the data of the temperature, rotation direction and rotation angle of the substrate to acquire data of the movement direction and an amount of positional error of the substrate, adjusting the position of the transfer unit based on data of the movement direction and the amount of positional error, transferring the substrate from the film-forming chamber, returning the substrate which was transferred out of the film-forming chamber, back into the film-forming chamber by the adjusted transfer unit, placing the substrate on the susceptor via the substrate-supporting portion, supplying the reaction gas into the film-forming chamber, and forming a predetermined film on the substrate while the substrate is heated.

Further to a second embodiment of this invention, the method for forming a film wherein the temperature of the substrate is measured on two or more alternative circumferences, that are on the outer periphery of the substrate, when the center of the substrate is aligned with the center of the susceptor.

Further to a second embodiment of this invention, the method for forming a film wherein the position of the transfer unit is adjusted when the amount of positional error is more than an allowable value.

A third embodiment of this invention, a film-forming method comprising: transferring a first substrate into a film-forming chamber via a transfer unit, and placing the first substrate on a susceptor via a substrate-supporting portion, measuring the temperature of the first substrate while the first substrate is rotating, and detecting the rotating direction and rotation angle of the first substrate, generating temperature data of the first substrate based on the data of the first temperature, rotation direction and rotation angle of the first substrate to acquire data of the movement direction and an amount of positional error of the first substrate, adjusting the position of the transfer unit based on data of the movement direction and the amount of positional error, transferring the first substrate out of the film-forming chamber, transferring a second substrate back into the film-forming chamber via the transfer unit wherein the second substrate consists of the same material as the first substrate, placing the second substrate on the susceptor via the substrate-supporting portion, supplying a reaction gas into the film-forming chamber to form a predetermined film on the second substrate while the second substrate is heated.

Further to a third embodiment of this invention, the method for forming a film wherein the temperature of the substrate is measured on the circumferences that are on the outer periphery of the substrate when the center of the substrate is aligned with the center of the susceptor.

Further to a third embodiment of this invention, the method for forming a film wherein the temperature of the substrate is measured on two or more circumferences that are on the outer periphery of the substrate when the center of the substrate is aligned with the center of the susceptor.

Further to a third embodiment of this invention, the method for forming a film wherein the position of the transfer unit is adjusted when the amount of positional error is more than an allowable value.

BRIEF DESCRIPTION OF THE DIAGRAMS

FIG. 1 is a schematic cross section of a film-forming apparatus according to the present embodiment showing a substrate supported by the transfer arm.

FIG. 2 is an example of the film-forming method according to the present embodiment showing the substrate supported by the substrate-supporting portion.

FIG. 3 is an example of the film-forming method according to the present embodiment showing the substrate on a susceptor.

FIG. 4 is a schematic diagram of the positions of the measurement of the temperature on the substrate.

FIG. 5 shows the relationship between the substrate and points for measuring the temperature.

FIG. 6 is an example of the temperature distribution on the circumferences of the substrate.

FIG. 7 is an example of the temperature distribution T1 of the temperature on the circumference 701.

FIG. 8 is a flowchart of data of the film-forming apparatus in the present embodiment.

FIG. 9 is a flowchart of the film-forming method in the present embodiment.

FIG. 10 is a schematic cross section of a conventional film-forming apparatus.

DETAILED DESCRIPTION OF INVENTION

FIG. 1 is a schematic cross section of a film-forming apparatus according to the present embodiment. In this diagram, some components are omitted except the necessary components to explain the present embodiment. The scale of this diagram is different from an actual apparatus so that each component is visible clearly.

As shown in FIG. 1, a film-forming apparatus 100 has a film-forming chamber 1. The film-forming chamber 1 has a belljar-shaped body 102 on the base plate 101. A base plate cover 103 is positioned, and is detachable from, the base plate 101, the base plate cover 103 has a shape and size which can cover the whole of the base plate 101. The material of the base plate cover 103 may be, for example, quartz. The base plate 101 is connected with the belljar-shaped body 102 via a flange 10. The flange 10 is sealed with packing 11. The base plate 101 is made of, for example, SUS (Steel Use Stainless).

During the vapor-phase growth reaction, the temperature is very high in the film-forming chamber 1. Therefore, flow channels 3 of cooling water for cooling the film-forming chamber 1 are positioned in the base plate 101 and the belljar-shaped body 102.

The belljar-shaped body 102 has a supply portion 5 for supplying a reaction gas 4. The base plate 101 has a discharge portion 6. After the reaction the resulting process gases, that is the process gas and the denatured gas, are exhausted through the discharge portion 6 out of the film-forming chamber 1.

The discharge portion 6 is connected to a pipe 12 via the flange 13. Packing 14 seals the flange 13. The packing 11 and 14 may be made of a material such as fluoro rubber (as one example) having a capacity for heat resistance of approximately 300° C.

A hollow column-shaped liner 2 is positioned in the film-forming chamber 1. The liner 2 is positioned between an inner wall 1 a of the film-forming chamber 1 and a space ‘A’ in which the vapor-phase growth reaction is performed on the substrate 7. This liner 2 prevents the inner wall 1 a from being is damaged by the reaction gas 4. As the epitaxial reaction is performed at high temperature, the liner 2 should consist of materials having a high capacity for heat resistance, for example, SiC or carbon-coated SiC.

In the present embodiment, the liner 2 is separated into a body portion 2 a and a top portion 2 b for ease of explanation. The body portion 2 a is a part in which the susceptor 8 is placed. The top portion 2 b has a smaller inner diameter than the body portion 2 a. The liner 2 consists of the body portion 2 a and the top portion 2 b combined into one body. The top portion 2 b is positioned above the body portion 2 a.

A shower plate 15 is fitted into the upper opening of the top portion 2 b. The shower plate 15 functions as a flow-straightening vane for uniformly supplying the reaction gas 4 to the surface of the substrate 7. The shower plate 15 has a plurality of through-holes 15 a thereon. When the reaction gas 4 is supplied from the supply portion 5 into the film-forming chamber 1, the reaction gas 4 flows downward to the substrate 7 through the through-holes 15 a. It is preferable that the reaction gas 4 can be efficiently focused on the surface of the substrate 7 without wasting the reaction gas 4. Accordingly, the inner diameter of the top portion 2 b is designed so as to be smaller than the body portion 2 a. Specifically the inner diameter of the top portion 2 b is determined in consideration of the position of the through-holes 15 a and the size of the substrate 7.

The susceptor 8 for supporting the substrate 7 is positioned in the film-forming chamber 1, specifically, in the body portion 2 a of the liner 2. In order to form a SiC epitaxial film, the temperature of the substrate 7 needs to be 1500° C. or higher. For this reason, the susceptor 8 needs to be made of highly heat-resistant material. A susceptor 8 obtained by coating the surface of isotropic graphite with SIC by CVD (Chemical Vapor Deposition) is used (as one example). The shape of the susceptor 8 is not particularly limited as long as the substrate 7 can be placed on the susceptor 8, and may be designed as required. Examples can include a ring shape and a solid disk shape.

The heater 9 positioned in the rotating cylinder 17 heats the substrate 7. The heater 9 is a heater unit in the present invention. The heater 9 can be a resistive heater, and includes a disk shaped in-heater 9 a and a ring shaped out-heater 9 b. The in-heater 9 a is placed at the position corresponding to the substrate 7. The out-heater 9 b is placed above the in-heater 9 a, and at the position corresponding to outer periphery of the substrate 7. As the temperature of the outer periphery of the substrate 7 can be lower than the inner periphery, the combination of an in-heater and an out-heater can prevent a drop in temperature of the outer periphery.

The in-heater 9 a and the out-heater 9 b are supported by an electrically conductive arm-like busbar 20. The busbar 20 is made of, for example, a carbon-coated SiC material. The busbar 20 is supported by the heater base 21 made of quartz, at the opposite side of the in-heater 9 a and the out-heater 9 b. The busbar 20 are connected to conductive connecting portions 22. The conductive connecting portions 22 are formed of a metal such as molybdenum. Electricity can be conducted from rod electrodes 23 through the busbar 20 to the in-heater 9 a and the out-heater 9 b. Specifically, electricity is conducted from the rod electrodes 23 to a heat source of the in-heater 9 a and the out-heater 9 b, and then the temperature of the heat source will increase.

The surface temperature of the substrate 7 is measured by radiation thermometers 24 a and 24 b, as a temperature-measuring unit. In FIG. 1, the temperature at the center of the substrate 7 is measured by the radiation thermometer 24 a. The temperature of the outer position of the substrate 7 is measured by the radiation thermometer 24 b. The position of measuring the temperature, via the radiation thermometer 24 b, is capable of being moved along the periphery of the substrate 7. These radiation thermometers are positioned at the upper position of the film-forming chamber 1 as shown in FIG. 1. It is preferred that the upper portion of the belljar-shaped body 102 and the shower plate 15 be formed of quartz, because the use of quartz prevents the temperature measurement of the radiation thermometers 24 a and 24 b from being affected.

After temperature measurement the data is sent to a control unit (not illustrated) and then fed back to an output control unit of the in-heater 9 a and the out-heater 9 b. As an example, each temperature of these heaters can be set as follows, when SiC epitaxial film is formed on the substrate 7. Thereby the substrate 7 can be heated approximately 1650° C.

Temperature of in-heater 9 a: 1680° C. Temperature of out-heater 9 b 1750° C.

The rotating shaft 16 and the rotating cylinder 17 positioned on the top of the rotating shaft 16 are placed in the body portion 2 a of the liner 2. The rotating unit in the present invention comprises a rotating shaft 16 and the rotating cylinder 17. The susceptor 8 is attached on the rotating cylinder 17. The rotating shaft 16 is rotated, and then the susceptor 8 is rotated via the rotating cylinder 17. When the vapor-phase growth reaction is performed, the substrate 7 is placed on the susceptor 8, and the substrate 7 is rotated with the susceptor 8.

The rotating shaft 16 and the rotating cylinder 17 are attached to a rotating system 310 provided under the base plate 101. An encoder 300 used for monitoring the number of revolutions of the rotating shaft 16 and the rotating cylinder 17 provided in the rotating system 310. The encoder 300 monitors the number of revolutions, and the rotating shaft 16 and the rotating cylinder 17 are controlled so that the number of revolutions can be kept at a predetermined number. Further, the encoder 300 detects the rotating direction and the rotation angle of the substrate 7, placed on the rotating shaft 16 and the rotating cylinder 17. Therefore, in the present invention the encoder 300 acts as a detecting unit. The encoder 300 comprises an encoder head 304 for detecting the rotation of a rotating plate 305, and an encoder pickup 306 having a circuit substrate for processing a detected signal.

The reaction gas 4 passing through the shower plate 15, flows downward toward the substrate 7 via the top portion 2 b. The reaction gas 4 is attracted by the substrate 7 while the substrate 7 is rotating, and the reaction gas 4 forms a so-called vertical flow in a region extending from the shower plate 15 to the surface of the substrate 7. When the reaction gas 4 reaches the substrate 7, the reaction gas 4 flows without turbulence as a substantially laminar flow in a horizontal direction along the upper surface of the substrate 7. As described above, the reaction gas 4 comes into contact with the surface of the substrate 7, and an epitaxial film is formed on the surface of the substrate 7 by a pyrolytic reaction or a hydrogen reduction of the reaction gas 4 on the surface of the substrate 7. Further, the film-forming apparatus 100 is configured so that the gap between the periphery of the substrate 7 and the liner 2 is minimized to allow the reaction gas 4 to flow more uniformly onto the surface of the substrate 7.

According to the above-mentioned apparatus, the vapor-phase growth reaction is performed while the substrate 7 is heated and rotated. The reaction gas 4 can be efficiently supplied on the whole surface of the substrate 7, and then an epitaxial film having high thickness uniformity is formed. It is noted that the film-forming rate can be increased when reaction gas 4 is continuously supplied to the surface of the substrate 7.

The reaction gas not used for the vapor-phase growth reaction and the gas produced by the epitaxial reaction, is exhausted from the discharge portion 6 of the base plate 101.

FIG. 1, FIG. 2, and FIG. 3 show the substrate 7 being transferred into the film-forming chamber 1 and being placed on the susceptor 8.

A substrate transfer portion 46 is provided in the liner 2, and a substrate transfer portion 47 is provided in the belljar-shaped body 102. The film-forming chamber 1 is positioned adjacent to the transfer chamber (not shown) and is connected via the substrate transfer portion 47. A transfer robot as a component of the transfer unit is positioned in the transfer chamber. The transfer robot has a transfer arm 48. The position of the transfer arm 48 is adjusted so that the substrate 7 will be placed on the susceptor 8 so that the center of the substrate 7 is aligned with the center of the susceptor 8.

The substrate 7 is transferred from the transfer chamber to the film-forming chamber 1 by the transfer arm 48, through the substrate transfer portion 46 and 47, and is then transferred from the transfer arm 48 to the substrate-supporting portion 50 as shown in FIG. 2. The positional relationship between the position of the substrate 7, the position of the susceptor 8, and the position of the transfer arm 48 is adjusted in the transfer chamber so that the substrate 7 will be placed on the susceptor 8 in the ideal position so that the center of the substrate 7 aligns with the center of the susceptor 8. The positional relationship between the position of the transfer arm 48 and the position of the substrate-supporting portion 50 is adjusted so that the substrate 7 can be transferred from the transfer arm 48 to the substrate-supporting portion 50 while maintaining the correct alignment, thereby allowing the substrate 7 to be aligned correctly in the center position of the susceptor 8. After the substrate 7 is transferred to the substrate-supporting portion 50, the substrate-supporting portion 50 moves down to place the substrate 7 on the susceptor 8 as shown in FIG. 3.

In the above-mentioned process of transferring the substrate 7, the temperature in the transfer chamber is at approximately room temperature, but the temperature in the film-forming chamber 1 is higher than the temperature in the transfer chamber, for example 800° C., though this is lower than the temperature required for the vapor-phase growth reaction process. The substrate 7 transferred from the transfer chamber to the film-forming chamber 1 will be transformed because of the rapid change of temperature, resulting in the slightly movement on the transfer arm 48 or on the substrate-supporting portion 50. As a result, the position of the substrate 7 will be misaligned from the adjusted position and therefore the center of the substrate 7 will not align with the center of the susceptor 8.

In the present embodiment, the amount of positional error is determined, and then is fed back to the transfer robot before the vapor-phase growth reaction to correct positional error of the substrate 7.

As shown in FIG. 3 the transfer arm 48 is moved out of the film-forming chamber 1. After that, the temperature of the outer periphery of the substrate 7 is measured by the radiation thermometer 24 b while the substrate 7 is rotating at a low speed, for example about 50 rpm. After the measurement of the temperature of one circumference around the outer periphery is finished, the temperature of another circumference, a circumference in which the distance from the center of the substrate 7 differs at a predetermined distance from the previous circumference, will be measured as above. These measurements of the various circumferences will be performed once for each circumference. For example, the temperature of the circumference that is 95 mm away from the center of the silicon wafer, of which diameter is 8 inch, is measured. The position of the measurement is changed so that the distance from the center of the silicon wafer will be larger by increments of 1 mm after each measurement of one circumference is finished. These measurements are repeated five times, one for each of the circumferences.

FIG. 4 is a schematic diagram of the positions to have temperature measurement performed on the substrate 7. Area 7 a shows the outer periphery of the substrate 7. Area 8 a shows the counterbore of the susceptor 8. Area 8 b shows the sidewall of the counterbore 8 a. The temperature can be measured along each individual circumference 701-705 of the five circles whose center positions align with the center of the substrate 7 and have a different diameter to each other. When the substrate 7 is placed on the susceptor 8 when the center of the substrate 7 aligns with the center of the susceptor 8, the measurement result at each circumference 701-705 should be uniform. That is, the temperature values measured at the circumference 701 are substantially the same at any position of the circumference. This also applies to the other circumferences 702-705.

Though the points for measuring are not limited on five circumferences, it is preferred to be on two or more circumferences. The reason is as follows.

The surface of the substrate 7 is ideally parallel to the horizontal plane, but actually it has some waves, or variations in the plane, hereinafter referred to as a curve of the substrate 7. Accordingly from the point of a microscopic view, the substrate 7 cannot perfectly contact with the susceptor 8 and is partially apart from the susceptor 8. Thereby the temperature values would not distribute evenly on the circumference even if the substrate 7 is placed on the susceptor 8 when the center of the substrate 7 is aligned with the center of the susceptor 8. Therefore if the temperature of the outer periphery of the substrate 7 is measured on only one circumference, it is hard to distinguish the temperature caused by the misalignment between the center of the susceptor 8 and the center of the substrate 7, with the temperature caused by the curve of the substrate 7. Therefore the temperature is preferably measured on at least two circumferences in the present embodiment.

FIG. 5 shows the relationship between the positional error of the substrate 7 and the points for measuring the temperature. In FIG. 5, the area 7 a shows the outer periphery of the substrate 7 when the center of the susceptor 8 aligns with the center of the substrate 7. The area 7 b shows the outer periphery of the substrate 7 after the substrate 7 has moved along the direction of the arrow in FIG. 5, and as a result the center of the susceptor 8 no longer aligns with the center of the substrate 7.

As shown in FIG. 5, the distance from the outer periphery of the substrate 7 to the sidewall 8 b of the counterbore of the susceptor 8 is shorter in the direction of the arrow and therefore longer in the opposite direction of the arrow. When the epitaxial reaction is performed under this condition, part of the reaction gas gathers where the outer periphery 7 b is close to the sidewall 8 b of the counterbore, resulting in the formation of an epitaxial film. This film attaches the substrate 7 to the susceptor 8, which may hamper the transfer of the substrate 7, or generate slip.

Area 700 in FIG. 5 corresponds to Area 700 in FIG. 4. That is, each of the five points surrounded by the area 700 in FIG. 5, are on the circumferences 701-705 in FIG. 4. Each of the five points surrounded by the area 700′ in FIG. 5, are on the circumferences 701-705 in FIG. 4. For example, the point which is closest to the outer periphery 7 a as shown in the area 700, and the point which is closest to the outer periphery 7 a as shown in the area 700′ are on the same circumference 701.

In the present embodiment, the temperature of the outer periphery of the substrate 7 is measured by the radiation thermometer 24 b as seen in FIG. 1-3. Therefore, the position for measuring the temperature will not change even if the substrate 7 is not in the correct position. This means the following.

In FIG. 4, five circumferences 701-705 are positioned on the outer periphery of the substrate 7 when the center of the susceptor 8 aligns with the center of the substrate 7. As shown in FIG. 5, three circumferences 703-705 (700 b) are positioned on the substrate 7 and two circumferences 701-702 (700 a) are partially out of the substrate 7. That is, three points (700 b) are on the substrate 7, and two points (700 a) are not on the substrate 7. However the temperature will be measured on five circumferences 701-705.

As shown in FIG. 1, the heater 9 heats the substrate 7. The susceptor 8 is positioned between the substrate 7 and the heater 9. Therefore, the temperature of the susceptor 8 is higher than the temperature of the substrate 7. Accordingly, when the temperature is measured on five circumferences 701-705 in FIG. 4 when the periphery of the substrate 7 is 7 b, the measurement by the radiation thermometer 24 b is for the susceptor 8 (specifically the counterbore 8 a) not the substrate 7 where the circumference is out of the substrate 7. Therefore the temperature at this point will be higher than the temperature at the point where the circumference is on the substrate 7.

For example, if the periphery of the substrate 7 is 7 a in FIG. 5, the temperature of five points in the part surrounded by the area 700, should be substantially the same as the temperature of corresponding five points in the part surrounded by the area 700′. However if the periphery of the substrate 7 will be 7 b as a result of positional error of the substrate 7, the part surrounded by the area 700 will be moved causing the substrate 7 to move away from the susceptor 8. As mentioned above, the temperature of the susceptor 8 is higher than the temperature of the substrate 7, therefore, the temperature of the part surrounded by the area 700 will be generally higher than the temperature if there is no positional error of the substrate 7, as shown in FIG. 4, because the susceptor 8 was moved to the side that the susceptor 8 is exposed from the substrate 7. However, the temperature of the part surrounded by the area 700′ will be generally lower than the temperature if there is no positional error of the substrate 7.

FIG. 6 is an example of the temperatures T1-T5 on the circumferences 701-705 in FIG. 4 when the periphery of the substrate 7 is 7 a in FIG. 5. The horizontal axis of the diagram shows a rotation angle between the rotating shaft 16 and the rotating cylinder 17 in FIG. 1. The positions on the circumference are decided by this rotation angle. The rotation angle 0 degree is the same position as the rotation angle 360 degrees. If the positions of each points in the part surrounded by the area 700 are the rotation angle of 90 degrees (as seen in FIG. 5), the positions of each points in the part surrounded by the area 700′ are the rotation angle 270 degrees.

The encoder 300 in FIG. 1 detects the rotation angle shown in the horizontal line of FIG. 6. The encoder 300 also detects the rotation direction of the rotating shaft 16 and the rotating cylinder 17. The position data of the coordinates used for the measurement of the temperature is created by the rotation direction and the rotation angle detected by the encoder 300.

In FIG. 6, the areas T1, T2, T3, T4 and T5 show each temperature on the circumference 701, 702, 703, 704 and 705 in FIG. 4. Each temperature is constant on any positions on the circumference. The temperature on one circumference is different from the temperature on other circumference. For example, as seen in FIG. 4, circumference 701 (which has the hottest temperature) is closest to the part of the susceptor 8 exposed from the substrate 7. Therefore, the temperature T1 shows the highest temperature. However, the circumference 705, as seen in FIG. 6) is the farthest from the part of the susceptor 8 exposed from the substrate 7, T5 shows the lowest temperature.

FIG. 7 is an example of the temperature T1 on the circumference 701 when the periphery of the substrate 7 is 7 b in FIG. 5. The horizontal axis of the diagram is the same as FIG. 6. The temperature of the counterbore 8 a (see FIG. 4) that is not covered with the substrate 7 is constant at any points on the susceptor 8.

In FIG. 7, the temperature T1 changes depending on the position on the circumference 701 in FIG. 4. In temperature T1, the highest temperature corresponds to the area A when the circumference 701 is out of the substrate 7 as in FIG. 4. Because the temperature of the counterbore 8 a of the susceptor 8, and not the substrate 7, is measured in the area A, it will be higher than the others. As the temperature in all the other areas except area A is measured on the substrate 7, the temperatures will be lower than area A. The circumference 701 in FIG. 4 is farther from the part of the susceptor 8 exposed from the substrate 7, that is, it is closer to the center of the substrate 7, therefore the temperature is lower. The lowest temperature corresponds to the points surrounded by area 700′ in FIG. 5.

Data of the movement direction and the amount of positional error of the substrate 7, that is, the direction and the amount of positional error between the center of the substrate 7 and the center of the susceptor 8, is acquired by comparing the temperature T1 of the temperature in FIG. 6 with the temperature T1 of the temperature in FIG. 7. In actuality, the temperatures on the circumferences 702-705 are acquired when the periphery of the substrate 7 is 7 b, and then the average of the temperatures on five circumferences is calculated. After that, data of the movement direction and the amount of positional error of the substrate 7 are acquired by comparing this average with the average of the temperatures T1-T5 in FIG. 6.

FIG. 8 is a flowchart of data of the film-forming apparatus in the present embodiment.

As shown in FIG. 8, a temperature-measuring unit 402 measures the temperature of the substrate 7 placed in the film-forming chamber 1. The temperature-measuring unit 402 has radiation thermometers 24 a and 24 b as seen in FIG. 1. The data measured by the temperature-measuring unit 402 is sent to a temperature data-generating unit 403. The temperature data-generating unit 403 generates temperature data for every substrate 7 placed in the chamber 1.

The encoder 300 detects the rotating direction and the rotation angle of the rotating shaft 16 and the rotating cylinder 17 in the film-forming chamber 1. The detected data is sent to the position data-generating unit 405. The position data-generating unit 405 generates the position data of the coordinates of the substrate 7 that should have a temperature measurement performed based on this position data.

The temperature data from the temperature data-generating unit 403 and the position data from the position data-generating unit 405 are sent to the data analysis unit 406. The data analysis unit 406 generates the temperature distribution data shown in FIG. 7 based on this data. Then, data of the movement direction and the amount of positional error of the substrate 7 are acquired by comparing this data with the standard temperature distribution data shown in FIG. 6.

Data of the movement direction and the amount of positional error of the substrate 7 acquired in the data analysis unit 406 are sent to a transfer robot control unit 407. The transfer robot control unit 407 adjusts the position of the transfer robot 408 (specifically the transfer arm 48), as seen in FIG. 1-3, based on data of the movement direction and the amount of positional error of the substrate 7. Thereby the position of the transfer arm 48 will be adjusted to the position taking into consideration the amount of positional error if the substrate 7 was transformed by the difference in temperature between the transfer chamber and the film-forming chamber 1, and then moved or shifted from its original position on the transfer arm 48 or the substrate-supporting portion 50. Therefore, the substrate 7 will be placed at the position on the susceptor 8 where the center of the substrate 7 aligns with the center of the susceptor B. Accordingly, as the distance from the substrate 7 to the sidewall 8 b of the counterbore of the susceptor 8 will be uniform along the circumference, the situation can be prevented wherein an epitaxial film is formed as the result of the reaction gas 4 between the substrate 7 and the sidewall 8 b, acting to attach the substrate 7 to the susceptor 8, which may cause a slip in the substrate 7 as well as hampering the transfer of the substrate 7. Further, an epitaxial film having a uniform thickness can be formed if the substrate 7 is placed on the susceptor 8 so that the center of the substrate 7 aligns with the center of the susceptor 8.

In the present embodiment, an operator can manually adjust the position of the transfer robot 408 based on data of the movement direction and the amount of positional error of the substrate 7 acquired by the data analysis unit 406.

Next, an example of the film-forming method in the present embodiment will be described referring to FIG. 1, FIG. 2, FIG. 3, FIG. 8 and FIG. 9. FIG. 9 is a flowchart of the film-forming method according to the present embodiment.

The film-forming apparatus 100 according to the present embodiment is preferable for forming a SiC epitaxial film. The following mentions one example of SiC epitaxial film forming.

For example, a SiC wafer can be used as the substrate 7. The substrate 7 is not limited to the SiC wafer. The material of the substrate 7 may be, for example, Si, SiO2 (quartz) or another insulator material. A highly resistive semi-insulating substrate such as GaAs (gallium arsenide) can also be used.

In the present embodiment, the position of the substrate is adjusted before the SiC epitaxial film forming. Firstly, the substrate 7 is transferred into the film-forming chamber 1 by the transfer arm 48 as shown in FIG. 1 (see S101). Next, the substrate 7 is transferred from the transfer arm 48 to the substrate-supporting portion 50 as shown in FIG. 2 (see S102). Then the substrate-supporting portion 50 moves down to place the substrate 7 on the susceptor 8 as shown in FIG. 3 (see S103).

Next, the temperature is measured while the substrate 7 is rotating (see S104). Specifically the susceptor 8 is rotated at low speed via the rotating cylinder 17 by the rotation of the rotating shaft 16. The number of revolutions of the substrate 7 can be rotated at approximately 50 rpm (as one example). Then, the temperature of the outer periphery of the substrate 7 is measured by the radiation thermometer 24 b while the substrate 7 is rotating. For example, the temperature is measured on one circumference of the outer periphery. After that, the distance from the center of the substrate 7 is changed, and then another measurement is performed on another circumference. This measurement process is repeated for each circumference to be measured. During the measurement, the encoder 300 detects the rotating direction and the rotation angle of the rotating shaft 16 and the rotating cylinder 17. After S104, the substrate is stopped rotating, and then the substrate 7 is transferred out of the film-forming chamber 1.

Next, the temperature data and the position data are generated by the measurement result using the radiation thermometer 24 b and the detection result by the encoder 300 (see S105). Specifically, the measurement value from the radiation thermometer 24 b is sent to the temperature data-generating unit 403, and then the temperature data-generating unit 403 generates the temperature data of every substrate 7. The data detected by the encoder 300 is sent to the position data-generating unit 405. The position data-generating unit 405 generates the position data of the coordinates of the substrate 7 based on this data.

Next, data of the movement direction and the amount of positional error of the substrate 7 are acquired based on the temperature data and the position data (see S106). Specifically, the temperature data from the temperature data-generating unit 403 and the position data from the position data-generating unit 405 are sent to the data analysis unit 406. The data analysis unit 406 generates the temperature distribution data shown in FIG. 7 based on this data. Then data of the movement direction and the amount of positional error of the substrate 7 are acquired by comparing this data with the standard data shown in FIG. 6.

Next, the amount of positional error acquired in S106 is determined to be at an allowable value or less than the allowable value (see S107). This decision is performed in the data analysis unit 406 shown in FIG. 8.

If the amount of positional error is more than the allowable value, the position of the transfer arm 48 is adjusted in the transfer chamber (see S108). Specifically, data of the movement direction and the amount of positional error of a first substrate 7 acquired in the data analysis unit 406 are sent to the transfer robot control unit 407. The position of the transfer robot 408 (specifically the transfer arm 48) is adjusted based on data of the movement direction and the amount of positional error of the first substrate 7 by the transfer robot control unit 407. After this process of determining data of the movement direction and the amount of positional error a film can be formed on the first substrate, in this case, the quality of the film caused by any potential positional error can be examined in an inspection process after the film-forming process. Alternatively, a second substrate of the same construction can be placed into the film-forming chamber by the substrate-supporting portion 50 (after removal of the initial substrate) (see S109). In this case the initial substrate acts as a guide template to accurately determine positional error.

The data analysis unit 406 then determines if the transfer arm needs to be adjusted. If the amount of positional error is at the allowable value or less than the allowable value, the position of the transfer arm 48 does not need to be adjusted, and then a substrate 7 that will be used for film-forming after an initial substrate 7, used for detecting the movement direction and the amount of positional error, is transferred into the film-forming chamber 1 without the position adjustment of the transfer arm 48 (see S109). Then an epitaxial film will be formed on the substrate 7 (see S110).

The substrate 7 used for detecting the movement direction and the amount of positional error can, after positional correction, have an epitaxial film formed thereon. For example, if the amount of positional error is more than the allowable value in S107, the substrate 7 used for detecting the movement direction and the amount of positional error is transferred out of the film-forming chamber 1 to adjust the position of the transfer arm 48 in the transfer chamber (see S108). At that time, the transfer arm 48 can be manually adjusted by the operator, based on data of the movement direction and the amount of positional error, or can be automatically adjusted by the transfer robot control unit 407. After adjustment of the position, the initial substrate 7 used for detecting the movement direction and the amount of positional error is transferred into the film-forming chamber 1 again, and placed on the susceptor 8 by the substrate-supporting portion 50 (see S109). After that, an epitaxial film will be formed on the substrate 7 (see S110).

The data analysis unit 406 then determines if the transfer arm needs to be adjusted. If the amount of positional error is at the allowable value or less than the allowable value, the position of the transfer arm 48 does not need to be adjusted. Therefore the step progresses from S107 to S110 to form an epitaxial film on the substrate 7 without transferring the substrate 7 out of the film-forming chamber 1.

In the present embodiment, a substrate 7 that is to be transferred into the film-forming chamber 1 in S109, should be the same material as the substrate 7 used for measuring data of the movement direction and the amount of the position error. For example, if the initial substrate 7 is made from silicon wafer then the substrate 7 for having a film formed thereon should also be made from silicon wafer. In this situation, the adjustment of positional error can be performed to all substrates of a similar construction. If a substrate is the same material as another substrate then data of the movement direction and the amount of positional error is generally similar. A substrate for forming a film thereon that is not the same as another substrate used for measuring a movement direction and an amount of positional error can still be placed so that the center of the substrate aligns with the center of the susceptor 8 by the adjustment of the position of the transfer arm 48 based on data of the movement direction and the amount of positional error. This is preferred for increasing throughput of the film-forming process.

Further the data of the movement direction and the amount of positional error including zero positional error can be sent to the transfer robot control unit 407 without the above-mentioned decision in the data analysis unit 406, and then the adjustment of the transfer arm 48 can be performed.

According to the above-mentioned process, even if the substrate 7 was transformed by the difference in the temperatures between the transfer chamber and the film-forming chamber 1, and as a result was moved on the transfer arm 48 or the substrate-supporting portion 50, the position of the transfer arm 48 will be adjusted in consideration of the amount of positional error. Therefore the substrate 7 will be placed on the susceptor 8 wherein the center of the substrate 7 aligns with the center of the susceptor 8. Accordingly, the adjustment to the position of the substrate can be performed to only the first substrate of a specific selection of substrates that are continuously transferred in the film-forming process, or the adjustment to the position of the substrate can be performed to every substrate on which a film will be formed.

After the substrate 7 is placed on the susceptor 8, an epitaxial film is formed on the substrate 7 by the epitaxial reaction (see S110).

As a reaction gas 4, for example, propane (C₃H₈) or silane (SiH₄) is used. Hydrogen gas is used as the carrier gas. In the case of the reaction gas 4, disilane monochlorosilane (SiH₃C1), dichlorosilane (SiH₂Cl₂), torichlorosilane (SiHCl₃) or tetrachlorosilane (SiCl₄) can also be used instead of silane.

Next, the substrate 7 is rotated at atmospheric pressure or under an appropriate reduced vacuum pressure. The susceptor 8 on which the substrate 7 is placed is positioned on the upper end of the rotating cylinder 17. When the rotating cylinder 17 is rotated via the rotating shaft 16, the susceptor 8 can be rotated via the rotating cylinder 17, and consequently the substrate 7 can be rotated via the susceptor 8. The number of revolutions that the substrate 7 can be rotated at is approximately 50 rpm (as one example).

The heater 9 then heats the substrate 7. During the vapor-phase growth reaction, the substrate 7 is heated at the predetermined temperature, for example, between 1500° C. and 1700° C. At this time an excessive increase in the temperature of the film-forming chamber 1 can be prevented by allowing cooling water to flow through the flow channel 3, provided in the base plate 101 and the belljar-shaped body 102.

After it is confirmed that the temperature of the substrate 7 measured by the radiation thermometer 24 a and 24 b has reached a predetermined temperature, for example 1650° C., the number of revolutions of the substrate 7 is gradually increased. For example, the number of revolutions of the substrate 7 can be increased to 900 rpm. Further, the reaction gas 4 is supplied from the supply portion 5.

The reaction gas 4 passes through the through holes 15 a of the shower plate 15, and then flows into the space ‘A’ in which the vapor-phase growth reaction will be performed on the substrate 7. At this time, the flow of the reaction gas 4 is straightened by allowing the reaction gas 4 to pass through the shower plate 15 serving as a flow-straightening vane so that the reaction gas 4 flows in a substantially vertical direction downward toward the rotating substrate 7 placed under the shower plate 15. That is, the reaction gas 4 forms a so-called vertical flow.

When the reaction gas 4 reaches the surface of the substrate 7, a thermal decomposition reaction or a hydrogen reduction reaction occurs thereby forming a SiC epitaxial film on the surface of the substrate 7. Surplus reaction gas 4 that was not used for the vapor-phase growth reaction, and gas generated by the vapor-phase growth reaction, is discharged through the discharge portion 6 provided in the lower part of the film-forming chamber 1.

After forming a SiC film of a predetermined thickness on the substrate 7, the supply of reaction gas 4 is stopped. The heating is then stopped and the operator will wait until the temperature of the substrate decreases to a predetermined temperature. The gas in the film-forming chamber 1 is then replaced with hydrogen gas, an inert gas and so on. The supply of the carrier gas can also be stopped at the same time, alternatively, after only the supply of the reaction gas 4 is stopped, the supply of the carrier gas can also be stopped after the temperature of the substrate 7 as measured by the radiation thermometer 24 a, 24 b becomes lower than a predetermined temperature.

After the temperature of the substrate 7, as measured by the radiation thermometer 24 a and 24 b, is cooled to a predetermined temperature, the substrate 7 is moved out of the film-forming chamber 1.

Specifically the substrate-supporting portion 50 is moved up to contact the substrate 7, and then continues to travel upwards with the substrate 7. Thereby, the substrate 7 is moved upward as shown in FIG. 2. Next, the substrate 7 is transferred from the substrate transfer portion 50 to the transfer arm 48. After that, the substrate 7 is transferred out of the film-forming chamber 1 through the substrate transfer portion 47 while being held by the transfer arm 48.

A new substrate 7 is transferred into the film-forming chamber 1 to continue film forming. As mentioned above, if the substrate is made from the same material as the initial substrate, the amount of positional error is similar. Therefore, the new substrate 7 can be transferred into the film-forming chamber 1 without second positional adjustment by the transfer arm 48. However, second positional adjustment can be performed according to S101-S109, and then, the epitaxial film can be formed on the substrate 7 according to the above-mentioned process.

According to the present embodiment, the position of the transfer arm 48 will be adjusted in consideration of data of the movement direction and the amount of positional error even if the substrate 7 was transformed by the difference of the temperature between the transfer chamber and the film-forming chamber 1, and as a result was moved on the transfer arm 48 or the substrate-supporting portion 50. Therefore, the substrate 7 will be positioned on the susceptor 8 where the center of the substrate 7 aligns with the center of the susceptor 8. Accordingly, as the distance from the substrate 7 to the sidewall 8 b of the counterbore of the susceptor 8 will be uniform along the circumference, it can prevent the reaction gas 4 from gathering and forming an epitaxial film between the substrate 7 and the sidewall 8 b, thereby the film acts to attach the substrate 7 to the susceptor 8, which cause a slip in the substrate 7 as well as hampering the transfer of the substrate 7. Further, a film having a uniform thickness can be formed as the substrate 7 is placed on the susceptor 8 so that the center of the substrate 7 aligns with the center of the susceptor 8.

Features and advantages of the present invention can be summarized as follows.

The first embodiment in the present invention provides a film-forming apparatus which can place the substrate on a predetermined position on the susceptor in spite of the temperature difference between the transfer chamber and the film-forming chamber, because the film-forming apparatus comprises an analysis unit for acquiring data of the movement direction and an amount of positional error of the substrate, and a control unit for adjusting the position of the transfer unit based on data of the movement direction and the amount of positional error.

The second embodiment of the present invention provides a film-forming method which can place the substrate on a predetermined position on the susceptor in spite of the temperature difference between the transfer chamber and the film-forming chamber, because the film-forming method comprises a process for acquiring data of the movement direction and an amount of positional error of the substrate, and a process for adjusting the position of the transfer unit based on data of the movement direction and the amount of positional error.

The third embodiment of the present invention provides a film-forming method which can transfer a first substrate into a film-forming chamber via a transfer unit, measure the temperature of the first substrate while the first substrate is rotating to acquire data of the movement direction and an amount of positional error of the first substrate then adjust the position of the transfer unit based on data of the movement direction and the amount of positional error, transfer the first substrate out of the film-forming chamber, transfer a second substrate back into the film-forming chamber and form a predetermined film on the second substrate while the second substrate is heated.

The present invention is not limited to the embodiments described above and can be implemented in various modifications without departing from the spirit of the invention. For example, the above embodiment has been described as an example of a film-forming process while rotating the substrate in a film-forming chamber, the present invention is not limited to this. The film-forming apparatus of the present invention may be deposited on the substrate while stationary and not rotating.

In addition to the above embodiments, an epitaxial growth system cited as the example of a film-forming apparatus for forming SiC film in the present invention is not limited to this. Reaction gas supplied into the film-forming chamber for forming a film on the surface of a substrate while heating the substrate can also be applied to other apparatus like a CVD (Chemical Vapor Deposition) film-forming apparatus, and to form other epitaxial film.

The above description of the invention has not specified apparatus constructions, control methods, etc. which are not essential to the description of the invention, since any suitable apparatus constructions, control methods, etc; can be employed to implement the invention.

Further, the scope of this invention encompasses all film-forming apparatus employing the elements of the invention and variations thereof, which can be designed by those skilled in the art. 

What is claimed is:
 1. A film-forming apparatus comprising: a film-forming chamber for being supplied a reaction gas; a susceptor for placing a substrate on, provided in the film-forming chamber; a heater for heating the substrate, provided below the susceptor; a transfer chamber being adjacent to the film-forming chamber; a transfer unit for transferring the substrate to the film-forming chamber, provided in the transfer chamber; a temperature-measuring unit for measuring temperature of the substrate; a rotating unit for rotating the substrate via the susceptor; a detecting unit for detecting rotating direction and rotation angle of the rotating unit; an analysis unit for generating temperature distribution data of the substrate using temperature data of the substrate measured by the temperature-measuring unit while the substrate is rotating, and positional data of coordinates at which temperature is measured, generated based on the rotating direction and the rotation angle detected by the detecting unit, and the analysis unit for acquiring data of the movement direction and an amount of positional error of the substrate based on the temperature distribution data; a control unit for adjusting position of the transfer unit based on data of the movement direction and the amount of position error of the substrate.
 2. The film-forming apparatus according to claim 1, wherein the analysis unit determines whether the amount of positional error is at an allowable value or less than the allowable value, and sends data of the movement direction and the amount of positional error to the control unit if the amount of positional error is more than the allowable value.
 3. The film-forming apparatus according to claim 1, wherein the temperature-measuring unit has a radiation thermometer provided outside the film-forming chamber to measure a temperature of the substrate, by receiving radiant light from the substrate.
 4. The film-forming apparatus according to claim 3, wherein the location of temperature measurement on the substrate, performed via the radiation thermometer, is capable of being moved.
 5. The film-forming apparatus according to claim 4, wherein the location of temperature measurement on the substrate is capable of moving a predetermined distance.
 6. The film-forming apparatus according to claim 3, wherein the temperature-measuring unit has a first radiation thermometer for measuring a temperature of the center position of the substrate by receiving the radiant light from the substrate, and a second radiation thermometer for measuring a temperature of the periphery of the substrate.
 7. The film-forming apparatus according to claim 6, wherein the location of temperature measurement on the substrate, performed via the second radiation thermometer, is capable of being moved.
 8. The film-forming apparatus according to claim 7, wherein the location of temperature measurement on the substrate by the second radiation thermometer is capable of moving a predetermined distance.
 9. The film-forming apparatus according to claim 1, wherein the heating unit has a first heater for heating the substrate, and a second heater for heating the periphery of the substrate.
 10. A film-forming method comprising: transferring a substrate into a film-forming chamber by a transfer unit, and placing the substrate on a susceptor by a substrate-supporting portion; measuring a temperature of the periphery of the substrate while the substrate is rotating and detecting the rotating direction and rotation angle of the substrate; generating temperature distribution data of the substrate based on the data of the temperature, rotation direction and rotation angle of the substrate to acquire data of a movement direction and an amount of positional error of the substrate; adjusting the position of the transfer unit based on the data of the movement direction and the amount of positional error; transferring the substrate from the film-forming chamber; returning the substrate which was transferred out of the film-forming chamber, back into the film-forming chamber by the adjusted transfer unit; placing the substrate on the susceptor by the substrate-supporting portion; supplying the reaction gas into the film-forming chamber, and forming a predetermined film on the substrate while the substrate is heated.
 11. The film-forming method according to claim 10, wherein the temperature of the substrate is measured on two or more alternative circumferences, that are on the outer periphery of the substrate, when the center of the substrate is aligned with the center of the susceptor.
 12. The film-forming method according to claim 10, wherein the position of the transfer unit is adjusted when the amount of positional error is more than an allowable value.
 13. A film-forming method comprising: transferring a first substrate into a film-forming chamber by a transfer unit, and placing the first substrate on a susceptor by a substrate-supporting portion; measuring the temperature of the first substrate while the first substrate is rotating, and detecting the rotating direction and rotation angle of the first substrate; generating temperature distribution data of the first substrate based on the data of the first temperature, rotation direction and rotation angle of the first substrate to acquire data of a movement direction and an amount of positional error of the first substrate; adjusting the position of the transfer unit based on the data of the movement direction and the amount of positional error; transferring the first substrate out of the film-forming chamber; transferring a second substrate back into the film-forming chamber by the transfer unit wherein the second substrate consists of the same material as the first substrate; placing the second substrate on the susceptor by the substrate-supporting portion; supplying a reaction gas into the film-forming chamber to form a predetermined film on the second substrate while the second substrate is heated.
 14. The film-forming method according to claim 13, wherein the temperature of the substrate is measured on the circumferences that are on the outer periphery of the substrate when the center of the substrate is aligned with the center of the susceptor.
 15. The film-forming method according to claim 14, wherein the temperature of the substrate is measured on two or more circumferences that are on the outer periphery of the substrate when the center of the substrate is aligned with the center of the susceptor.
 16. The film-forming method according to claim 13, wherein the position of the transfer unit is adjusted when the amount of positional error is more than an allowable value. 